Electric system

ABSTRACT

The disclosure embraces an electric system including a gas discharge arc lamp construction of a character particularly for use in the graphic arts field and a transformer power circuit for a gas discharge arc lamp wherein an increased voltage for momentarily effecting gas ionization and establishment of the arc is attained through the summation of a peak charge of applied alternating current voltage of a capacitor occurring during onehalf cycle applied directly to the lamp in series with the applied voltage from the transformer during the alternate half cycle and thereafter shorting out the capacitor for applying the normal voltage of the transformer to the arc lamp for normal operation.

United States Patent Kiefer et al.

[ Sept. 18, 1973 ELECTRIC SYSTEM Assignee: Holophane CompanyIncorporated,

New York, NY.

Filed: July 26, 1971 Appl. No.: 166,034

U.S. Cl. 315/227, 315/DIG. 5, 315/240, 315/276, 315/362 Int. Cl. H05b39/04 Field of Search 313/44; 3l5/DIG. 5, 315/200, 223, 225, 226, 227,240, 241, 254, 276, 362

References Cited UNITED STATES PATENTS 11/1951 Bird 3l5/DIG. 5 11/1938Wood 313/44 X Primary Examiner-Roy Lake Assistant ExaminerLawrence J.Dahl Attorney-Harry O. Ernsberger [57] ABSTRACT The disclosure embracesan electric system including a gas discharge arc lamp construction of acharacter particularly for use in the graphic arts field and atransformer power circuit for a gas discharge arc lamp wherein anincreased voltage for momentarily effecting gas ionization andestablishment of the arc is attained through the summation of a peakcharge of applied a1- temating current voltage of a capacitor occurringduring one-half cycle applied directly to the lamp in series with theapplied voltage from the transformer during the alternate half cycle andthereafter shorting out the capacitor for applying the normal voltage ofthe transformer to the arc lamp for normal operation.

7 Claims, 6 Drawing Figures PATENTED SEP1 8 I973 'snmlafz INVENTOR.

Z AL W. Raams W 0. W

TOP/VEV ELECTRIC SYSTEM This invention relates to an electric systeminvolving a gas discharge arc lamp of a character particularly for usein the graphic arts field, the lamp embodying a power circuit for thegas discharge arc lamp utilizing the voltage of a transformer secondaryfor normal arc operation and wherein an increased voltage is establishedthrough capacitor means sufficient to effect establishment of the arcand wherein alternating current is employed for normal lamp operation.

Lamps of the character heretofore used in the graphic arts field haveembodied special ignition transformers and devices to provide highvoltage alternating current for ignition of a gas discharge are lamp andthereafter a reduced voltage direct current utilized for normal lampoperation.

In the use of a gas discharge lamp in the graphic arts field it has beena practice to de-energize the gas discharge lamp after each exposureoperation. In making successive short exposures, considerable time isinvolved in bringing the gas discharge lamp to an operating temperatureand cooling the lamp preparatory to a subsequent exposure operation.

The present invention embraces a lamp construction embodying a gasdischarge are lamp and a power circuit or electric system thereforwherein alternating current of high voltage is provided forestablishment or ignition of the gas discharge lamp and alternatingcurrent voltage of a transformer utilized for normal operation of thelamp, and the power for the lamp reduced during standby periods wherebyde-energization of the lamp between successive periods of normaloperation of the lamp may be avoided.

An object of the invention embraces a power system or circuit for a gasdischarge are lamp wherein a high alternating current starting voltagefor igniting the lamp is attained through the summation of the voltageof a half cycle of applied alternating current of a transformer with thevoltage of a capacitor charged to the peak of applied alternatingcurrent voltage occurring duringthe alternate half cycle and whereby thelamp upon ignition operates at a normal alternating current voltage fromthe transformer.

Another object of the invention resides in the provision of a lampstructure wherein the lamp enclosure is provided with a shutter movableto light exposing and light obstructing positions and a circuit systemfor a shutter drive motor arranged to provide dynamic electric breakingof the motor for preventing over-travel of the shutter in its movementsfrom one position to the other.

Another object of the invention resides in a lamp construction embodyinga gas discharge are lamp and a power circuit therefor for operating thelamp at a high power level and for operating the lamp at a low powerstandby level.

Another object of the invention is the provision of a lamp structureincluding a gas discharge are lamp and reflector means therefor disposedin a housing and multiple blower means in the housing wherein one bloweris effective for venting the lamp housing and another blowersupplementing the first blower rendered operative during high poweroperation of the lamp to effectively cool the arc lamp.

Another object of the invention embraces an electric system or powercircuit wherein the summation of alternating current voltage from atransformer and the peak voltage of a capacitor is employed for ignitionof a gas discharge lamp and alternating current voltage from the sametransformer utilized for normal operation of the lamp in conjunctionwith control means for continued energization of the lamp at standby lowpower operation whereby the lamp is maintained at an elevatedtemperature during lower power operation in readiness for high poweroperation thereby eliminating warm up periods for the lamp.

Further objects and advantages are within the scope of this inventionsuch as relate to the arrangement, operation and function of the relatedelements of the structure, to various details of construction and tocombinations of parts, elements per se, and to economics of manufactureand numerous other features as will be apparent from a consideration ofthe specification and drawing of a form of the invention, which may bepreferred, in which:

FIG. 1 is a side elevational view, partly in section, of a lampconstruction embodying a gas discharge arc lamp;

FIG. 2 is a front elevational view of the lamp construction shown inFIG. 1;

FIG. 3 is a rear elevational view of the lamp construction;

FIG. 4 is a rear elevational view of the lamp construction with the rearcover removed;

FIG. 5 is a semischematic view of a shutter or curtain for the exposureopening of the lamp housing, and

FIG. 6 is a schematic diagram of the power circuit of the invention forthe ignition and operation of the gas discharge are lamp.

While the gas discharge arc lamp construction and power circuit of theinvention have particular utility for lighting exposure purposes in thegraphic arts field, it is to be understood that the arc lampconstruction and power circuit therefor may be used wherever the samemay be found to have utility.

Referring to the drawings, the arc lamp construction illustrated is of acharacter particularly usable in the photocopy and graphic arts field.The lamp construction is inclusive of a base 20 provided with casterwheels 21 and having a hollow boss which receives the lower end of anupwardly extending tubular support member 22 secured in place by a bolt23. Telescoped into the tubular member 22 is a second tubular member 24,at the upper end of which is mounted a bracket 26 supporting arectangular lamp housing 28 secured to the bracket by screws 27. Thehousing 28 is preferably fashioned of sheet metal and is provided with aremovable rear cover or closure member 29.

Surrounding the tubular support member 24 is a circular clamp 30 whichis split as at 31 and is equipped with a clamp screw 32. As shown inFIG. 1, the clamp member provides an adjustable abutment engageable withthe upper end of the tubular member 22. By ma- .nipulating the clampingscrew 32, the position of the 7 support tube 24 may be adjusted relativeto the tube 22 for varying the height of the lamp housing 28 withrespect to the base 20. A second housing 34, mounted upon the base 20,encloses a transformer and other electrical components of the system.

A housing or casing 36 secured to an exterior wall of the lamp housing28 encloses a timing means or timer for the lamp. As shown in FIG. 2,the timer housing 36 supports an adjustable timing member 38 whichcooperates with indicia 39 indicating minutes, the member 38 beingadjustable to vary the operational periods of the lamp. Disposed withinthe lamp housing 28 are bus bars or supports 42 connected with a currentsupply. Each bus bar 42 is equipped with a clip or member 44 forsupporting a gas discharge lamp or lamp bulb 46 of elongated shape, theclips engaging end regions of the lamp envelope.

As an example, the hollow region of the lamp envelope may beapproximately 4 inches or more in length providing an arc of desiredlength. The bulb or lamp 46 is of a conventional type containing mercuryand preferably a metal additive such as a halide to concentrate theradiant energy in a desired spectral range. Disposed in the housing 28is a reflector 48 supported by frame members 50, shown in FIG. 4.

The reflector 48 is of curved configuration such as a partial sphericalor ellipsoidal shape for reflecting rays of light from the lamp 46forwardly through a glazed window 52 shown in FIG. 1. A supplementallight reflecting or guiding means 54 fashioned of sheet metal isdisposed in the housing forwardly of the reflector 48, the reflector 54being of generally frusto-pyramidal shape provided by four convergingwalls 56, shown in FIGS. 1 and 2.

A casing or supplemental housing 58, illustrated in FIGS. 1 and 4,disposed in the lamp housing 28 encloses electrical control componentsin addition to those contained within the base housing 34. The powersupply is connected with a transformer disposed in the housing 34 aswell as other components of the power circuit, the circuit connectionsfor the components disposed in the housing 58 being contained within asheath or cable 60, shown in FIG. 1, connected by a titting 61 with ahousing 58, a slot 62 in the cover member 29 accommodating the fitting61. The timer contained within the housing 36 is connected withcomponents in the housing 34 by connections contained within a sheath 64shown in FIG. 1.

Means is provided in the lamp housing 28 for ventilating the lamphousing and for directing a stream of air into the region of the gasdischarge lamp 46 for cooling the lamp when the lamp is in high poweroperation. The housing ventilating means includes a blower or fan 66driven by a motor B1 preferably supported in the housing 28 adjacent therear cover member 29. The rear cover member 29 is provided with ascreened opening 68 for admitting air into the lamp housing 28 under theinfluence of the rotating fan or blower 66. The side walls of thehousing 28 are provided with louvers 70, shown in broken lines in FIG.1, to facilitate circulation of air through the lamp housing.

A second blower or blower means 72 is disposed in the lamp housingrearwardly of the reflector 48, the air exit tube 74 of the blower beingaligned with an opening 76 at the central region of the reflector 48whereby a stream of air from the blow is'delivered through the opening76 to the region of the gas discharge lamp 46. The opening 76 isprovided with a grid 78 to effect diffusion of the air delivered towardthe lamp 46. The blower 72 is driven by a motor 82 which is energized ashereinafter describedthrough the timer means contained in the housing36, the blower 72 being operated only when the gas discharge lamp 46 isoperating under full power.

A relatively movable curtain or shutter means is provided forobstructing passage of light from the are except when an exposure ismade for a graphic reproduction. The arrangement is inclusive ofaflexible impervious curtain, shutter or light obstructing means 80illustrated in FIGS. 1 blower 5, the curtain and associated componentsbeing shown in detail in FIG. 5. Disposed at an upper frontal regionwithin the housing 28 is a horizontal roll 82 having tenon portions 82joumaled in openings in the side walls of the lamp housing 28.

Secured to the lower end of the curtain or shutter 80 is a transverselyextending bar 85, a second bar 86 being secured to the other end of thecurtain, the bars being movable with the curtain. Joumally supported atthe lower frontal corners of the housing 28 are pulleys 88, a second setof pulleys 90, shown in FIG. 5, being disposed adjacent the lowermid-region of the housing. Secured to the respective ends of the bar arecables 92, each cable being engaged with pulleys 88 and 90 in the mannershown in FIG. 5. The ends of the cables adjacent the pulleys 90 aresecured to a clip or connector 94.

Connected to the respective ends of the bar 86 is a cable 96, the cable96 being connected at its midregion with a clip or connector 98. Joinedwith the connectors 94 and 98 are the end regions of a flexible member,cable or tape 100 which, as shown in FIG. 5, is engaged with pulleys 102and 103 disposed at the central upper and lower regions in the housingadjacent the rear cover 29. Mounted upon a support plate or member 105mounted within the lamp housing 28 is a motor B3 of a conventionalreversible type, the shaft of which is equipped with a drive roll 107.Idler or tape guiding rolls 109 are journally mounted for rotation onthe plate 105.

As particularly shown in FIG. 5, the tape or member 100 is engaged withthe idler rolls 109 and extends partially around the drive roll 107. Aroll 1 1 1, mounted on an arm or lever 112 pivoted on the plate 105, isbiased into engagement with the tape 100 at the region of the drive roll107 by means of a contractile spring 115 connected to an end of thelever 112 and the plate 105. The contractile spring 115 exerts pressureon the roll 111 to assure a drive connection between the driving roll107 and the tape 100. The light obstructing means or curtain 80 is shownin open position in FIGS. 1 and 5, that is, in a position where lightfrom the lamp 46 passes unobstructed through the glass 52.

With particular reference to FIG. 5, it will be apparent that uponrotation of the motor B3 in the proper direction, the tape 100 will bemoved in a direction to move the curtain 80 into a position obstructingthe pas-v sage of light from the lamp housing. The movement of thecurtain 80 to light obstructing position is determined by a limit switchS3, and the movement of the curtain 80 to open position is determined bylimit switch S4. The use of the flexible tape 100 facilitates openingand closing movements of the curtain or light In order to initiateignition of and form an arc in the gas discharge lamp 46 and prepare thecomponents for automatic lamp operation, the switch S2 is moved toclosed position. The switch S1 is closed supplying alternating current,for example, sixty cycle alternating current of 250 volts, to theprimary 118 of the transformer T1. The transformer provides alternatingcurrent of H5 volts to the control circuit through the circuit breakerCB1. As an example, a voltage of about 350 volts in the secondary 120 ofthe transformer is supplied to the circuit of the gas discharge lamp 46through a capacitor CI, but it is to be understood that a transformerproviding a higher or lower secondary voltage may be employed dependingupon the characteristics of the gas discharge lamp.

secondary voltage of the transformer is sensed by relay K1 or otherswitch means through a resistor R2, and the relay or switch means K1 isenergized. Energization of the relay Kl opens contacts 5 and 8 of relayK1 preventing operation of relay or switch means K3. Contacts 1 and 3 ofrelay K1 are closed and such action connects the diodes CR1 and CR2 inseries with a fuse F across the gas discharge are lamp 46 and in serieswith the capacitor C1 across the secondary 120 of the transformer T1.The closing of contacts 1 and 3 of the relay K1 establishes a shunt ofthe relay or switch K2 protecting the relay K2 from high voltage.A'capacitor C3 is disposed in parallel with the diodes CR1 and CR2 inorder to prevent damage to the diodes in event of an excessive voltagesurge.

Through the circuitry above described, a high voltage is developed, forexample, 990 volts in the circuit of the gas discharge are lamp 46 whichis sufficient to effect current flow through the lamp 46 and ignite orenergize the lamp. During one-half cycle of the applied alternatingcurrent voltage from the secondary 120 of the transformer T1, thecapacitor C 1 is charged to the peak of the applied alternating currentvoltage, viz. 495 volts by current conduction through the diodes CR1 andCR2.

During the alternate half cycle, the diodes CR1 and CR2 do not conductcurrent, and the peak voltage of voltage of the transformer secondary120 and the voltage of the charged capacitor CI, for example, thesummation of the peak voltages being approximately 990 volts. This peakvoltage of 990 volts is amply sufficient to establish current flowthrough the gas discharge lamp 46 and thereby ignite the lamp. Thisaction is repeated every other half cycle untilthe lamp 46 is ignited.It is to be understood that gas discharge lamps may be employedrequiring transformers of different secondary voltages.

After current flow is established by the high voltage through the gasdischarge lamp, the voltage across the lamp 46 falls to a low value byreason of the capacitor C1 and the characteristics of the transformerT1. The voltage falls to a sufficiently low value as to de-energize therelay Kl. De-energiz'atio'n of the relay'Kl opens contacts 1 and 3 ofthe relay Kl which connects the voltage sensing relay K2 in the circuitin series with the diodes CR1 and CR2.

Contacts 5 and 8 of relay Kl close, this action energizing relay K3through the switch 52A and contacts 1 and 4 of relay K2. Energizing therelay K3 shorts out the capacitor C1 to place the arc lamp 46 directlyacross the secondary 120 of the transformer T1. Relay K3 has two sets ofcontacts K3 1 and 2 and K3 3 and 4. Contacts 1 and 2 of relay K3 closefirst, placing the resistor R1 in parallel with the capacitor C1. In avery short period of time, contacts 3 and 4 of relay K3 close, thisaction shorting out the capacitor C 1. The momentary preclosing ofcontacts 1 and 2 of relay K3 reduces arcing of contacts 3 and 4 of therelay K3.

The motor'B1, driving the housing ventilating fan 66, is energizedcontinuously when the main switch S1 is in closed position. The motorB3, for operating the shutter or curtain 80, is energized throughcontacts 1 and 4 of the relay or switch means K4 and the normally closedcontacts (N.C.) of limit switch S3 to close the shutter or curtain 80,this is, to move the shutter or curtain to the position covering theopen end of the reflector 54.

When the shutter is closed, the motor B3 is deenergized and dynamicelectric braking is applied to the fields of the motor B3 by the openingof the normally closed (N.C.) contacts of the switch S3 and the closingof the normally open (N.C.) contacts of the switch S3 to reduceovertravel of the shutter or curtain to a minimum.

As the arc lamp 46 warms up, the voltage across the arc lamp increases.When the voltage reaches a predetermined value, which indicates that thelamp 46 is sufficiently warmed up, relay K2 is energized through thediodes CR1 and CR2 and the resistor R3. A capacitor C2 is provided forthe purpose of preventing relay chatter of the relay contacts. Aresistor R4 is disposed across the capacitor C2 for preventing a highvoltage occurring across the capacitor C2 in event that the coil ofrelay K2 is open.

As relay K2 is energized, contacts 4 and 1 of relay K2 open and contacts1 and 3 of relay K2 close. This contact action de-energizes relay K3.the contacts 1, 2 and 3, 4 of relay K3 open, placing the capacitor C1 inseries with the arc lamp 46 and reducing the power to the lamp 46 to astandby level. Contacts'8 and 6 of relay K2 close. The foregoingoperations occur in warming up the gas discharge lamp 46 and suchactions require a period of about 1 minute, the lamp now being instandby operation in readiness for automatic operation in makingexposures or reproductions. which require high power for the lamp.

The length of time of an exposure is controlled by a manually adjustabletimer motor B4 contained within the timer housing 36. The timerarrangement is shown schematically in FIG. 6 and includes a push buttonswitch 122, a timer switch 124 and a timer relay 126. In making anexposure, the operator manually moves the arm 38 of the timer to aposition indicating the time duration of the desired exposure in minutesindicated by the indicia 39.

The operator then closes the push button switch 122 energizing thetimer. The relay K3 is energized through the energization of the timerand contacts 5 and 8 of the relay Kl. The pairs of contacts of relay K3close, shorting out the capacitor C1 so that the arc lamp 46 receivesthe full power from the secondary of the transformer T1 for making anexposure. The motor B2 is energized through the timer and closedcontacts 8 and 6 of the relay K2 rotating the blower 72 to direct astream of air through the opening 76 in the reflector 48 into the regionof the arc lamp 46 to cool the lamp to a nominal operating temperature.

Relay K4 is energized through the timer and through the closed contacts1 and 3 of the relay K2. Energizing relay K4 opens the contacts 1 and 4of relay K4 and closes the contacts 1 and 3 of relay K4. This actionopens the dynamic braking circuit through the fields of the shutteroperating motor B3 and energizes the drive motor B3 through the closedcontacts 1 and 3 of relay K4 and the normally closed contacts of thelimit switch S4 whereby the operation of the motor B3 opens the shutter80.

When the shutter is opened, the drive motor B3 is deenergized anddynamic braking is applied through normally open'contacts of switch S4,diodes CR3, CR4 and resistors R and R6 to the fieldsof the motor B3, thedynamic braking action preventing over-travel of the shutter at theterminus of its opening movement. At the expiration of the time intervalfor which the timer has been set, the relay K3 is de-energized and itscontacts open, placing the capacitor C1 in series with the arc lamp 46,which action reduces the power supplied to the lamp 46, placing the lampin a standby condition.

The blower motor B2 is de-energized and relay K4 is de-energized.Contacts 1 and 3 of relay K4 open deenergizing the dynamic brakingcircuit for the motor B3. Contacts 1 and 4 of the relay K4 close,energizing the drive motor B3 through the normally closed (N.C.)contacts of the switch S3. This action energizes the motor B3 whichcloses the shutter. When the shutter is closed,- the motor B3 isde-energized and dynamic braking applied to the motor B3 throughnormally open (N.O.) contacts of switch D3, diodes CR3, CR4 andresistors R5 and R6 to the fields of the motor preventing over-travel ofthe motor when the shutter has been moved to closed position.

This completes a cycle of operations in carrying on an exposure tocompletion and a closing of the shutter. The circuit and lamp are now incondition for a subsequent automatic operation in making an exposuresimply by closing the switch 122.

During standby operation, the lamp 46 is operating under a lower powercondition at a warm up temperature, the motor B2 for driving the blower72 is deenergized, but the housing cooling fan 66 continues operation asthe motor Bl for operating the ventilating fan 66 is energized as longas power is supplied to the transformer T1. In order to de-energize thegas discharge lamp 46 and the motor Bl driving the ventilating fan 66,it is only necessary to move the main switch S1 to open circuitposition.

Through the arrangement above described, the secondary voltage of thesingle transformer T1 is summated with the peak voltage of'the capacitorC1 during the two half cycles of the alternating current frequencyproviding substantially double the voltage of the secondary 120 of thetransformer so that a sufficiently high voltage is established at thelamp 46 to effect ionization and ignition of the gas discharge are lamp46 without the necessity of using a special starting transformer orother devices which have heretofore been necessary in establishing theignition of a gas discharge are lamp.

Furthermore, the arrangement of blower 72 provides for special coolingofthe arc lamp 46 during high power operation of the lamp, the specialcooling system for the lamp supplementing the continuously operatingventilating system for the lamp housing. The arrangement of theinvention provides normal alternating current for the gas discharge lampthus eliminating rectifier means heretofore used for powering a gasdischarge arc lamp after ignition has been established.

While two diodes CR1 and CR2 are illustrated for establishing, throughthe capacitor C1, an increased voltage for igniting the are, it is to beunderstood that a single diode or diode means of sufiicient capacity maybe utilized for the purpose.

Through the use of a single transformer for both lamp ignition andnormal lamp operation, the energy efficiency of the system is improvedover prior systems. The dynamic braking system for the shutter operatingmotor accomplishes several advantages. It avoids the liability ofovertravel of the shutter when the shutter reaches open and closedpositions. In the dynamic braking system, the diodes CR3 and CR4 providea direct current braking effect to all of the fields of the motor, acondition which enables the braking current to be applied and maintainedto the motor fields except when the shutter is being moved from oneposition to the other. By applying braking current to all of the motorfields, a maximum braking effect is obtained, and as the current isapportioned among the several fields, the dynamic braking current may becontinued without overheating the motor. With the shutter-operatingmotor B3 dynamically locked in either open or closed position of theshutter, there is no liability for the shutter to creep'as the motordoes not operate except through the time delay relay.

It is apparent that, within the scope of the invention, modificationsand different arrangements may be made other than as herein disclosed,and the present disclosure is illustrative merely, the inventioncomprehending all variations thereof.

We claim:

1. An electric system including a gas discharge lamp, a housing for saidlamp, a transformer connected with a supply of alternating current forthe lamp, a circuit for the lamp including a capacitor in series withthe secondary of the transformer and the gas discharge lamp, a diodeacross the gas discharge lamp and in series with the capacitor acrossthe secondary of the transformer whereby during one-half cycle thecapacitor is charged to peak voltage by conduction of the diode andduring the alternate half cycle the peak voltage charge of the capacitoris applied to the gas discharge lamp in series with the appliedtransformer voltage of the alternate half cycle providing increasedvoltage sufficient to establish an arc in the lamp, and switch meansoperable upon establishment of the are for shunting the capacitorwhereby the lamp receives full power from the transformer.

2. An electric system including a gas discharge lamp, a housing for saidlamp, a transformer connected with a supply of alternating current forthe lamp, a circuit for the lamp including a capacitor in series withthe secondary of the transformer and the gas discharge lamp, a pair ofdiodes across the gas discharge lamp and in series with the capacitoracross the secondary of the transformer whereby during one-half cyclethe capacitor is charged to peak voltage by conduction of the diodes andduring the alternate half cycle the peak volt age charge of thecapacitor is applied to the gas discharge lamp in series with theapplied transformer voltage of the alternate half cycle providingincreased voltage sufficient to establish an arc in the lamp, and switchmeans operable upon establishment of the arc for shunting the capacitorwhereby the lamp receives full power from the transformer.

3. An electric system including a gas discharge lamp, a housing for thedischarge lamp, a circuit for establishing an arc in the gas dischargelamp including a transformer connected with a supply of alternatingcurrent for supplying current to the lamp, a capacitor in series withthe secondary of the transformer and the gas discharge lamp, diodemeans, switch means for connect ing the diode means across the gasdischarge lamp and in series with the capacitor across the secondary ofthe transformer whereby the capacitor is charged to peak voltage throughthe diode means during one-half cycle, the peak voltage of the capacitorbeing summated with the applied voltage from the secondary of thetransformer during the alternate half cycle providing increased voltageapplied to the gas discharge lamp sufficient to establish an arc, andsecond switch means operable upon establishment of the are for shuntingthe capacitor whereby the lamp receives full power from the transformer.

4. An electric system including a gas discharge lamp, a housing for saidlamp, a transformer connected with a supply of alternating current forthe lamp, a circuit for the lamp including a capacitor in series withthe secondary of the transformer and the gas discharge lamp, diodemeans, first switch means in closed position connecting the diode meansacross the gas discharge lamp and in series with the capacitor acrossthe secondary of the transformer whereby during one-half cycle thecapacitor is charged to peak voltage by conduction of the diode meansand during the alternate half cycle the peak voltage charge of thecapacitor is applied to the gas discharge lamp in series with theapplied voltage of the alternate half cycle from the secondary of thetransformer providing increased voltage for establishing an arc in thelamp, second switch means, said first switch means being opened afterthe arc is established under.

the influence of reduced voltage of the established arc and said secondswitch means activated upon opening of the first switch means to shortout the capacitor and thereby place the arc lamp across the secondary ofthe transformer to warm up the lamp establishing high power level ofoperation of the lamp, and voltage responsive means actuated byincreased voltage of the warmed lamp to actuate the second switch meansplacing the capacitor in series with the lamp and thereby reducing thepower level of the lamp to standby condition.

5. The system according to claim 4 including manually actuated timermeans operable for actuating said second switch means to short out thecapacitor whereby the lamp receives full power from the transformer, ablower in said housing for directing a stream of air toward the lamp forcooling the lamp, a motor for operating the blower, saidmotor beingenergized through the timer means for rendering the blower motoroperable during periods of high power operation of the lamp.

6. An electric system including a gas discharge lamp, a housing for saiddischarge lamp, a transformer connected with a supply of alternatingcurrent for the lamp, a circuit for the lamp including a capacitor inseries with the secondary of the transformer and the gas discharge lamp,diode means, first switch means in closed position connecting the diodemeans across the gas discharge lamp and in series with the capacitoracross the secondary of the transformer whereby during one-half cyclethe capacitor is charged to peak voltage by conduction of the diodemeans and during the alternate half cycle the peak voltage charge of thecapacitor is applied to the gas discharge lamp in series with theapplied voltage of the alternate half cycle from the secondary of thetransformer providing a peak voltage applied to the lamp substantiallytwice the peak voltage from the transformer for establishing the arc,said first switch means being opened after the arc is established underthe influence of reduced voltage of the established arc, second switchmeans, said second switch means being activated upon opening of thefirst switch means to short out the capacitor and thereby place the arclamp across the secondary of the transformer to warm up the lamp andestablish high power level of operation of the lamp, voltage responsivemeans actuated by increased voltage of the warmed lamp to actuate thesecond switch means placing the capacitor in series with the lamp andthereby reducing the power level of the lamp to standby condition, anadjustable timer for determining the duration of high power level ofoperation of the lamp, said second switch means being operable throughthe timer to short out the capacitor and establish high power level ofop eration of the lamp.

7. An electric system including a gas discharge lamp, a housing for thedischarge lamp, a circuit for the lamp including a transformer connectedwith a supply of alternating current, said circuit including a capacitorin series with the secondary of the transformer and the gas dischargelamp, means for establishing an arc in the gas discharge lampincludingdiode means, a first relay in closed position connecting thediode means across the gas discharge lamp and in series with thecapacitor across the secondary of the transformer whereby duringone-half cycle the capacitor is charged to peak volt age through thediode means and during the alternate half cycle the peak voltage chargeof the capacitor and the peak voltage of the alternate half cycle ofapplied voltage from the transformer are applied in series to the gasdischarge lamp for establishing an arc in the lamp,

said first relay means being de-energized by reduced voltage across thearc and to connect a voltage sensing means in circuit with the diodemeans, said voltage sensing means being arranged to energize a secondrelay to short out the capacitor and thereby place the arc directlyacross the secondary of the transformer to warm up the lamp, a voltageresponsive relay means actuated by increased voltage of the warmed lampto actuate the second relay to place the capacitor in series with thelamp thereby reducing the power level of the lamp to standby condition,timer means in the circuit adapted to be adjusted to time the durationof high power operation of the lamp, said second relay means beingoperable through the timer to short out the capacitor and establish highpower operation of the lamp during the period for which the timer isadjusted.

. k t II t

1. An electric system including a gas discharge lamp, a housing for saidlamp, a transformer connected with a supply of alternating current forthe lamp, a circuit for the lamp including a capacitor in series withthe secondary of the transformer and the gas discharge lamp, a diodeacross the gas discharge lamp and in series with the capacitor acrossthe secondary of the transformer whereby during one-half cycle thecapacitor is charged to peak voltage by conduction of the diode andduring the alternate half cycle the peak voltage charge of the capacitoris applied to the gas discharge lamp in series with the appliedtransformer voltage of the alternate half cycle providing increasedvoltage sufficient to establish an arc in the lamp, and switch meansoperable upon establishment of the arc for shunting the capacitorwhereby the lamp receives full power from the transformer.
 2. Anelectric system including a gas discharge lamp, a housing for said lamp,a transformer connected with a supply of alternating current for thelamp, a circuit for the lamp including a capacitor in series with thesecondary of the transformer and the gas discharge lamp, a pair ofdiodes across the gas discharge lamp and in series with the capacitoracross the secondary of the transformer whereby during one-half cyclethe capacitor is charged to peak voltage by conduction of the diodes andduring the alternate half cycle the peak voltage charge of the capacitoris applied to the gas discharge lamp in series with the appliedtransformer voltage of the alternate half cycle providing increasedvoltage sufficient to establish an arc in the lamp, and switch meansoperable upon establishment of the arc for shunting the capacitorwhereby the lamp receives full power from the transformer.
 3. Anelectric system including a gas discharge lamp, a housing for thedischarge lamp, a circuit for establishing an arc in the gas dischargelamp including a transformer connected with a supply of alternatingcurrent for supplying current to the lamp, a capacitor in series withthe secondary of the transformer and the gas discharge lamp, diodemeans, switch means for connecting the diode means across the gasdischarge lamp and in series with the capacitor across the secondary ofthe transformer whereby the capacitor is charged to peak voltage throughthe diode means during one-half cycle, the peak voltage of the capacitorbeing summated with the applied voltage from the secondary of thetransformer during the alternate half cycle providing increased voltageapplied to the gas discharge lamp sufficient to establish an arc, andsecond switch means operable upon establishment of the arc for shuntingthe capacitor whereby the lamp receives full power from the transformer.4. An electric system including a gas discharge lamp, a housing for saidlamp, a transformer connected with a supply of alternating current forthe lamp, a circuit for the lamp including a capacitor in series withthe secondary of the transformer and the gas discharge lamp, diodemeans, first switch means in closed position connecting the diode meansacross the gas discharge lamp and in series with the capacitor acrossthe secondary of the transformer whereby during one-half cycle thecapacitor is charged to peak voltage by conduction of the diode meansand during the alternate half cycle the peak voltage charge of thecapacitor is applied to the gas discharge lamp in series with theapplied voltage of the alternate half cycle from the secondary of thetransformer providing increased voltage for establishing an arc in thelamp, second switch means, said first switch means being opened afterthe arc is established under the influence of reduced voltage of theestablished arc and said second switch means activated upon opening ofthe first switch means to short out the capacitor and thereby place thearc lamp across the secondary of the transformer to warm up the lampestablishing high power level of operation of the lamp, and voltageresponsive means actuated by increased voltage of the warmed lamp toactuate the second switch means placing the capacitor in series with thelamp and thereby reducing the power level of the lamp to standbycondition.
 5. The system according to claim 4 including manuallyactuated timer means operable for actuating said second switch means toshort out the capacitor whereby the lamp receives full power from thetransformer, a blower in said housing for directing a stream of airtoward the lamp for cooling the lamp, a motor for operating the blower,said motor being energized through the timer means for rendering theblower motor operable during periods of high power operation of thelamp.
 6. An electric system including a gas discharge lamp, a housingfor said discharge lamp, a transformer connected with a supply ofalternating current for the lamp, a circuit for the lamp including acapacitor in series with the secondary of the transformer and the gasdischarge lamp, diode means, first switch means in closed positionconnecting the diode means across the gas discharge lamp and in serieswith the capacitor across the secondary of the transformer wherebyduring one-half cycle the capacitor is charged to peak voltage byconduction of the diode means and during the alternate half cycle thepeak voltage charge of the capacitor is applied to the gas dischargelamp in series with the applied voltage of the alternate half cycle fromthe secondary of the transformer providing a peak voltage applied to thelamp substantially twice the peak voltage from the transformer forestablishing the arc, said first switch means being opened after the arcis established under the influence of reduced voltage of the establishedarc, second switch means, said second switch means being activated uponopening of the first switch means to short out the capacitor and therebyplace the arc lamp across the secondary of the transformer to warm upthe lamp and establish high power level of operation of the lamp,voltage responsive means actuated by increased voltage of the warmedlamp to actuate the second switch means placing the capacitor in serieswith the lamp and thereby reducing the power level of the lamp tostandby condition, an adjustable timer for determining the duration ofhigh power level of operation of the lamp, said second switch meansbeing operable through the timer to short out the capacitor andestablish high power level of operation of the lamp.
 7. An electricsystem including a gas discharge lamp, a housing for the discharge lamp,a circuit for the lamp including a transformer connected with a supplyof alternating current, said circuit including a capacitor in serieswith the secondary of the transformer and the gas discharge lamp, meansfor establishing an arc in the gas discharge lamp including diode means,a first relay in closed position connecting the diode means across thegas discharge lamp and in series with the capacitor across the secondaryof the transformer whereby during one-half cycle the capacitor ischarged to peak voltage through the diode means and during the alternatehalf cycle the peak voltage charge of the capacitor and the peak voltageof the alternate half cycle of applied voltage from the transformer areapplied in series to the gas discharge lamp for establishing an arc inthe lamp, said first relay means being de-energized by reduced voltageacross the arc and to connect a voltage sensing means in circuit withthe diode means, said voltage sensing means being arranged to energize asecond relay to short out the capacitor and thereby place the arcdirectly across the secondary of the transformer to warm up the lamp, avoltage responsive relay means actuated by increased voltage of thewarmed lamp to actuate the second relay to place the capacitor in serieswith the lamp thereby reducing the power level of the lamp to standbycondition, timer means in the circuit adapted to be adjusted to time theduration of high power operation of the lamp, said second relay meansbeing operable through the timer to short out the capacitor andestablish high power operation of the lamp during the period for whichthe timer is adjusted.